Field of the Invention
The present invention relates to a technique for measuring the amount of a catalyst supported on an object to be measured that has a metal catalyst layer.
Description of the Background Art
Solid polymer electrolyte fuel cells (hereinafter, also abbreviated as “PEFCs”) are fuel cells including a polyelectrolyte. For example, an ion exchange resin is used as an example of a solid polyelectrolyte. In a PEFC, positive and negative electrodes are located with the solid polyelectrolyte in between them, and hydrogen is supplied as a fuel to the negative electrode and oxygen or air is supplied to the positive electrode to cause electrochemical reactions and produce electricity.
For example, the use of hydrogen as a fuel causes a reaction expressed by the following formula at the negative electrode:H2→2H++2e−The use of oxygen as an oxidant causes a reaction expressed by the following formula and produces water at the positive electrode.½O2+2H++2e−→H2O
To maximize those reactions at the positive and negative electrode of the fuel cell, a catalyst layer that is mixed with the positive and negative electrodes is important.
Japanese Patent Application Laid-Open No. 2005-32668 relates to an improvement in the performance of a catalyst layer and describes that the amount of platinum to be used is controlled depending on the concentration and membrane thickness in the preparation of a carbon paste that supports a platinum catalyst. the distribution of membrane thicknesses or discrepancy caused by uneven distribution of platinum nanoparticles in the catalyst layer as a result of a coating process are examined using a fuel cell, which is an end product.
Japanese Patent Application Laid-Open No. 2008-288093 relates to an improvement in the performance of an electrolyte membrane. A catalyst layer is produced using a commonly-known method, and the distribution of membrane thicknesses or discrepancy caused by uneven distribution of platinum nanoparticles in the catalyst layer obtained as a result of a coating process are examined using a fuel cell, which is an end product.
In Japanese Patent Application Laid-Open No. 2005-32668, platinum and a platinum alloy are used as catalysts of a fuel cell, and the catalysts are supported on, for example, carbon black.
In International Publication WO 2012/090450, platinum serving as a catalyst is supported on a platinum colloid, and colloidal particles are supported on, for example, carbon black.
In Japanese Patent Application Laid-Open No. 2006-260909, a palladium alloy (palladium-cobalt alloy) using a non-platinum metal as a catalyst is supported on, for example, carbon black.
Since platinum and platinum alloys suggested by Japanese Patent Application Laid-Open Nos. 2005-32668 and 2008-288093 are rare and expensive and greatly affect the performance of fuel cells, the catalyst needs to be supported in proper amounts. Thus, examining discrepancies after the manufacture of cells as end products may be a big economic loss.
Non-platinum metal materials suggested by International Publication No. WO 2012/090450 are less expensive than platinum, but still needs to be supported in proper amounts because they greatly affect the performance of fuel cells. Thus, again, examining discrepancies after the manufacture of fuel cells as end products may be a big economic loss.